scholarly journals Spectrophotometric determination of tadalafil in pure and dosage forms

2011 ◽  
Vol 17 (2) ◽  
pp. 125-132 ◽  
Author(s):  
Kaf Al ◽  
Ayman Gouda

Two simple, rapid, and extractive spectrophotometric methods were developed for the determination of tadalafil (TDF) in both pure and tablet dosage form. These methods are based on the formation of ion-pair complexes between the basic nitrogen of the drug with bromocresol purple (BCP) and methyl orange (MO) in acidic buffer solution. The formed complexes were extracted with chloroform and measured at 410 and 425 nm using BCP and MO, respectively. Beer?s law was obeyed in the range 2.0-20 ?g mL?1 with correlation coefficient (n = 6) ? 0.9996. The molar absorpitivity, Sandell sensitivity, detection and quantification limits were also calculated. The composition of the ion pairs was found 1:1 by Job?s method. The proposed methods have been applied successfully for the analysis of TDF in pure and in its dosage forms. These developed methods were validated for accuracy and precision.

Author(s):  
RAGAA EL-SHEIKH ◽  
AHLAM E. ABD ELLATEIF ◽  
ESRAA AKMAL ◽  
AYMAN A. GOUDA

Objective: Three sensitive, simple, precise, reproducible, and validated spectrophotometric methods have been developed for the determination of anti-psychotic drug (asenapine maleate) in pure and pharmaceutical dosage forms. Methods: The methods are based on the formation of yellow-colored ion-pair complex between asenapine maleate and three acid dyes, namely, bromocresol purple (BCP), bromophenol blue (BPB) and bromothymol blue (BTB) with absorption maxima at 410, 414 and 416 nm, respectively. Several parameters such as pH, buffer type and volume, reagent volume, the sequence of addition and effect of extracting solvent were optimized. Results: Under the optimum experimental conditions, beer’s law is obeyed over the concentration ranges of 1.0–20, 1.0–14, and 1.0-16 μg/ml for BCP, BPB and BTB, respectively, with good correlation coefficients (0.9994-0.9998). The apparent molar absorptivity and Sandell’s sensitivity values are reported for all methods. The limit of detection (LOD) and the limit of quantification (LOQ) values are found to be 0.27, 0.30, and 0.25 μg/ml and 0.90, 1.0, and 0.83 μg/ml for BCP, BPB and BTB, respectively. The stoichiometric ratio of the formed ion-pair complexes was found to be 1:1 (drug: reagent) for all methods, as deduced by Job's method of continuous variation. Conclusion: The proposed methods were successfully applied for the determination of asenapine maleate in pharmaceutical formulations with good accuracy and precision. Statistical comparison of the results was performed using Student's t-test and variance ratio F-test at the 95% confidence level and there was no significant difference between the reported and proposed methods regarding accuracy and precision. Further, the validity of the proposed methods was confirmed by recovery studies via standard addition technique in accordance with ICH guidelines.


Author(s):  
Zeinab Adel Nasr ◽  
Noha S. Said ◽  
Sawsan A. Abdel-Razeq

Aims: Two spectrophotometric methods were developed and validated for the determination of sofosbuvir in presence of its alkaline degradate. Study Design: Ratio difference and ratio derivative methods were assisted for determination of sofosbuvir in presence of its alkaline degradate, laboratory-prepared mixtures and in tablet dosage forms. Place and Duration of Study: Pharmaceutical Analytical Chemistry Department, Faculty of Pharmacy (Girls), Al - Azhar University, between December 2019 and January 2020. Methodology: Two analytical methods were achieved and validated for the quantitative determination of Sofosbuvir in presence of its alkaline degradate. The first method was ratio difference (RD) method, where the UV absorption spectra of different concentrations of sofosbuvir were divided by the spectrum of a certain concentration (15 µg mL-1) as a devisor of its alkaline degradate to get the ratio difference spectra. Afterwards, the peak amplitudes difference between 253.7 and 243.5 nm were measured. The second method was the ratio derivative (1DR) method, where the first derivative of the ratio spectra (1DR) was obtained and its amplitude was measured at 247 and 268 nm. Good linearity was obtained over the concentration range of 3-15 µg mL-1 for the proposed methods. The proposed procedures were adopted for the selective determination of intact Sofosbuvir in presence of up to 80% of its degradation product. Sofosbuvir was exposed to different conditions as alkaline, acidic and oxidative degradation. Results: The proposed methods were developed and validated with good linearity range of 3-15 µg mL-1 for both methods, and also with good accuracy and precision. And the obtained results were statistically compared to those obtained by the reported method. Conclusion: Sofosbuvir was successfully determined by the proposed ratio difference and ratio derivative methods in bulk powder, laboratory prepared mixtures and tablet dosage form with good accuracy and precision. The methods were validated according to ICH guidelines. The results obtained were compared with those of the reported method and were found to be in good agreement.


2009 ◽  
Vol 92 (1) ◽  
pp. 131-137 ◽  
Author(s):  
Zeynep Aydomu ◽  
Asli Barla

Abstract Two accurate, easy spectrophotometric methods for the determination of doxazosin mesylate were described. The first method was based on the formation of ion-pair complexes with the acidic sulfophthalein dyes bromocresol purple (BCP) and bromophenol blue (BPB) in pH 3.3 and 4.5 citratephosphate buffer, respectively. The formed complexes were extracted into dichloromethane, and their absorbance was measured at 403 and 410 nm for BCP and BPB, respectively. The second method was based on the charge transfer reaction of the drug as an n-electron donor with either 2,3-dichloro-5,6-dicyano-1,4-benzoquinone (DDQ) or 7,7,8,8-tetracyanoquinodimethane (TCNQ) as -acceptors, to give colored radical anions. The absorbances of products were measured at 457 nm in acetonitrile and 838 nm in methanol for DDQ and TCNQ, respectively. Under the optimum reaction conditions, Beer's law was obeyed with a good correlation coefficient (r = 0.99970.9999) in the concentration ranges 3.018.0, 3.020.0, 15.095.0, and 10.0100.0 g/mL for the BCP, BPB, DDQ, and TCNQ methods, respectively. Limits of detection of the BCP, BPB, DDQ, and TCNQ methods were 0.314, 0.408, 1.935, and 1.610 g/mL, respectively. The limits of quantification were 1.045, 1.360, 6.449, and 5.367 g/mL, respectively. The parameters molar absorptivity, precision, accuracy, recovery, robustness, and stability constant were studied. The proposed methods were successfully applied for determination of the drug in tablets with good accuracy and precision. Statistical comparison of the results with those obtained by a reported method showed good agreement and indicated no significant difference in accuracy and precision.


2013 ◽  
Vol 96 (1) ◽  
pp. 42-51 ◽  
Author(s):  
Burcin Bozal ◽  
Mehmet Gumustas ◽  
Burcu Dogan -Topal ◽  
Bengi Uslu ◽  
Sibel A Ozkan

Abstract Voltammetric, chromatographic, and spectrophotometric methods were developed for the simultaneous determination of bisoprolol fumarate (BIS) and hydrochlorothiazide (HCZ). Differential pulse and square wave voltammetry techniques were used to analyze BIS and HCZ simultaneously by measuring at about 1400 and 1100 mV, respectively. RP-HPLC was the second method for simultaneous analysis of the compounds. The mixture of BIS, HCZ, and moxifloxacin as an internal standard was separated on an RP Zorbax Eclipse XDB-C18 column (150 × 4.6 mm, id, 5 μm particle size) using acetonitrile–15 mM phosphate (25 + 75, v/v) mobile phase at a 1.0 mL/min flow rate. The third method was based on first derivative of the ratio-spectra method obtained from the measurements of the amplitudes at 246 and 257 nm for BIS and HCZ, respectively. All the proposed methods were effectively applied for the simultaneous determination of BIS and HCZ in tablet dosage forms without any time-consuming extraction, sample preparation, or derivatization procedures.


Author(s):  
Sawsan A. Abdel-Razeq ◽  
Zeinab Adel Nasr ◽  
Noha S. Said

Aims: Two simple and sensitive stability- indicating methods were developed and validated for the quantitative determination of sofosbuvir in presence of its degradation products. Study Design: Ultra high performance liquid chromatography (UPLC), High performance thin layer chromatography (HPTLC) are developed for determination of sofosbuvir in presence of its degradation products, laboratory-prepared mixtures and in tablet dosage forms. Place and Duration of Study: Analytical Chemistry Department, Faculty of Pharmacy (Girls), Al-Azhar University, between August 2018 and March 2019. Methodology: Two simple and sensitive stability- indicating methods were developed and validated for the quantitative determination of Sofosbuvir in presence of its degradation products. The first method was an Ultra Performance Liquid Chromatography (UPLC) method, in which efficient separation was carried out on phenomenex kinetex 2.6 μm C18 100 A column using a mobile phase consisting of filtered and degassed mixture of 0.1% ortho-phosphoric acid in water and methanol with the ratio of (40:60% v/v) adjusted to pH 3.5, at a flow rate of 1 mL min-1 and UV detection at 260 nm at ambient temperature. The second method is a high performance- thin layer chromatographic one (HPTLC) in which chromatographic separation was performed on silica gel 60 F254 plates, with methanol – chloroform – ammonia (2.5: 6: 1.5 % v/v/v) as a developing system followed by densitometric determination at 261 nm. Sofosbuvir was subjected to stress conditions including alkaline, acidic and oxidative degradation. Results: Beer’s law was obeyed over the range of 1-20 μg mL–1 for UPLC and 2-12 μg / spot for HPTC with good accuracy and precision using the two procedures, respectively. Results obtained was statistically analysed and found to be in accordance with those given by the reported method. Conclusion: The proposed methods were successfully applied for the determination of sofosbuvir in bulk powder, laboratory prepared mixtures and pharmaceutical dosage form with good accuracy and precision. The methods were validated according to ICH guidelines. The results obtained were compared with those of the reported method and were found to be in good agreement.


2012 ◽  
Vol 9 (1) ◽  
pp. 89-92
Author(s):  
J. Sudhakar Reddy ◽  
MD. S. Maqsood Ahmed ◽  
I. E. Chakravarthy ◽  
K. Prabhavathi

A simple, sensitive and economical spectrophotometric method has been developed for the determination of zidovudine in commercial dosage forms. The method was based on the formation of chloroform extractable complex of zidovudine with wool fast blue. The absorbance of the extractable ion pair complex is measured at the wavelength of maximum absorbance 590 nm against the reagent blank treated similarly. Statistical analysis proves that the proposed methods are reproducible and selective for the estimation of zidovudine in bulk drug and in its tablet dosage form.


2001 ◽  
Vol 69 (2) ◽  
pp. 143-150 ◽  
Author(s):  
A. Amin ◽  
H. Khalli ◽  
H. Saleh

Three simple, accurate and sensitive spectrophotometric methods (A, B and C) for the determination of cefuroxime and ceftazidime in bulk samples and in dosage forms are described. They are based on the reaction with nitrous acid forming a nitroso derivatives which can be measured at λmax 350 and 355 nm for cefuroxime (I) and ceftazidime (II), respectively (method A) or by oxidation of drug I or II with an excess of freshly prepared hypobromite and the residual hypobromite was treated with sodium fluorescein at the optimum experimental conditions and measured at λmax at 517 nm (method B). Method C is based on the formation of tris (0-phenanthroline) iron(II) complex (ferroin) upon the oxidation of the studied drug I or II with an iron (III)-o-phenanthroline mixture in acetate buffer solution of pH 3.6 and measuring at λmax 509 nm. Regression analysis of Beer-Lambert plots showed good correlation in the concentration ranges 0.2 – 6.0, 0.2 – 3.2 and 0.1 – 5.6 μg ml−1 for methods A, B and C, respectively. The apparent molar absorptivity, Sandell sensitivity, detection and quantitation limits were calculated. For more accurate results, Ringbom optimum concentration range was 0.2 – 5.6 μg ml−1. The validity of the proposed methods was tested by analysing dosage forms containing the studied drugs I and II. The relative standard deviations were ≤ 1.25% with recoveries 98.6 – 101.4% .


2005 ◽  
Vol 88 (4) ◽  
pp. 1148-1154 ◽  
Author(s):  
Juan C Rodríguez ◽  
Julia Barciela ◽  
Sagrario García ◽  
Carlos Herrero ◽  
Rosa M Peña

Abstract Multivariate experimental design has been used to optimize 2 flow-injection spectrophotometric methods for the determination of indapamide in pharmaceutical dosage forms, both pure and commercial tablets. The methods are based on the oxidation of this drug with iron (III) in acidic medium and the subsequent formation of an intensive orange-red complex between the liberated iron (II) and 2,2′-bipyridyl or 1,10-phenanthroline reagents. Plackett-Burman designs were applied as a screening method to evaluate the most significant factors with few experiments. Central composite 23+ star designs were performed to evaluate the response surfaces. The methods have been fully validated and were applied successfully to the determination of indapamide in pure and pharmaceutical forms with good accuracy and precision. Therefore, the 2 proposed procedures are simple, inexpensive, and rapid flow methods for the routine determination of indapamide in pharmaceutical preparations.


2012 ◽  
Vol 9 (3) ◽  
pp. 1645-1654 ◽  
Author(s):  
K. Raghubabu ◽  
L. Shanti Swarup ◽  
B. Kalyanaramu ◽  
M. N. Rao ◽  
C. Ramdas

Two simple, sensitive and cost effective visible spectrophotometric methods (M1 and M2) have been developed for the determination of venlafaxine hydrochloride from bulk and tablet dosage forms. The method M1 is based on the formation of green colored coordination complex by the drug with cobalt thiocyanate which is quantitatively extractable into nitro benzene with an absorption maximum of 626.4 nm. The method M2 involves internal salt formation of aconitic anhydride, dehydration product of citric acid [CIA] with acetic anhydride [Ac2O] to form colored chromogen with an absorption maximum of 561.2 nm. The calibration graph is linear over the concentration range of 10-50 µg/mL and 8-24 µg/mL for method M1 and M2 respectively. The proposed methods are applied to commercial available tablets and the results are statistically compared with those obtained by the reference method and validated by recovery studies. The results are found satisfactory and reproducible. These methods are applied successfully for the estimation of the venlafaxine hydrochloride in the presence of other ingredients that are usually present in dosage forms.


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